Add options{} parameter to verify_recaptcha so we can pass privatekey…

… as a parameter, instead of using ENV

lib/recaptcha.rb

@@ -46,12 +46,13 @@ def recaptcha_tags(options = {})
 
     module Controller
       # Your private API key must be specified in the environment variable +RECAPTCHA_PRIVATE_KEY+
-      def verify_recaptcha(model = nil)
+      def verify_recaptcha(model = nil, options = {})
         return true if SKIP_VERIFY_ENV.include? ENV['RAILS_ENV']
-        raise ReCaptchaError, "No private key specified." unless ENV['RECAPTCHA_PRIVATE_KEY']
+        private_key   = options[:private_key] ||= ENV['RECAPTCHA_PRIVATE_KEY']
+        raise ReCaptchaError, "No private key specified." unless private_key
         begin
           recaptcha = Net::HTTP.post_form URI.parse("http://#{RECAPTCHA_VERIFY_SERVER}/verify"), {
-            :privatekey => ENV['RECAPTCHA_PRIVATE_KEY'],
+            :privatekey => private_key,
             :remoteip   => request.remote_ip,
             :challenge  => params[:recaptcha_challenge_field],
             :response   => params[:recaptcha_response_field]